What are you looking for in a case? One that is built like a tank and will protect the phone so if you drop it onto any surface from any realistic height it will protect the phone? Or are you looking for something lightweight whose function is to protect the phone for typical drops onto carpets and floors and also provide a better grip on the phone?
I opt for the lightweight and grippy option. I usually get a clear "slim fit" TPU case. They are inexpensive and look great. They do tend to yellow with time, some more quickly than others. If you're worried about the yellowing over time, you can get a black case or other colors.